[Mac] Enables drag N' drop for the buttons within the Browser Actions contain...

chrome/browser/cocoa/extensions/browser_actions_controller.mm

Index: chrome/browser/cocoa/extensions/browser_actions_controller.mm
===================================================================
--- chrome/browser/cocoa/extensions/browser_actions_controller.mm	(revision 42818)
+++ chrome/browser/cocoa/extensions/browser_actions_controller.mm	(working copy)
@@ -4,6 +4,7 @@
 
 #import "browser_actions_controller.h"
 
+#include <cmath>
 #include <string>
 
 #include "app/resource_bundle.h"
@@ -59,7 +60,7 @@
 // Useful in the case of a Browser Action being added/removed from the middle of
 // the container, this method repositions each button according to the current
 // toolbar model.
-- (void)repositionActionButtons;
+- (void)repositionActionButtonsAndAnimate:(BOOL)animate;
 // During container resizing, buttons become more transparent as they are pushed
 // off the screen. This method updates each button's opacity determined by the
 // position of the button.
@@ -90,7 +91,17 @@
 // Updates the image associated with the button should it be within the chevron
 // menu.
 - (void)actionButtonUpdated:(NSNotification*)notification;
-
+// Adjusts the position of the surrounding action buttons depending on where the
+// button is within the container.
+- (void)actionButtonDragging:(NSNotification*)notification;
+// Updates the underlying toolbar model and "snaps" the button into its proper
+// place within the button grid.
+- (void)actionButtonDragFinished:(NSNotification*)notification;
+// Moves the given button both visually and within the toolbar model to the
+// specified index.
+- (void)moveButton:(BrowserActionButton*)button
+           toIndex:(NSUInteger)index
+           animate:(BOOL)animate;
 // Handles when the given BrowserActionButton object is clicked.
 - (void)browserActionClicked:(BrowserActionButton*)button;
 // Returns whether the given extension should be displayed. Only displays
@@ -424,7 +435,18 @@
     [self updateOverflowMenu];
   }
 
-  [self repositionActionButtons];
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(actionButtonDragging:)
+             name:kBrowserActionButtonDraggingNotification
+           object:newButton];
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(actionButtonDragFinished:)
+             name:kBrowserActionButtonDragEndNotification
+           object:newButton];
+
+  [self repositionActionButtonsAndAnimate:NO];
   [containerView_ setMaxWidth:
       [self containerWidthWithButtonCount:[self buttonCount]]];
   [containerView_ setNeedsDisplay:YES];
@@ -455,28 +477,24 @@
     // No more buttons? Hide the container.
     [containerView_ setHidden:YES];
   } else {
-    [self repositionActionButtons];
+    [self repositionActionButtonsAndAnimate:NO];
   }
   [containerView_ setMaxWidth:
       [self containerWidthWithButtonCount:[self buttonCount]]];
   [containerView_ setNeedsDisplay:YES];
 }
 
-- (void)repositionActionButtons {
+- (void)repositionActionButtonsAndAnimate:(BOOL)animate {
   NSUInteger i = 0;
   for (ExtensionList::iterator iter = toolbarModel_->begin();
        iter != toolbarModel_->end(); ++iter) {
     if (![self shouldDisplayBrowserAction:*iter])
       continue;
-
-    CGFloat xOffset = kGrippyXOffset +
-        (i * (kBrowserActionWidth + kBrowserActionButtonPadding));
     BrowserActionButton* button = [self buttonForExtension:(*iter)];
     if (!button)
       continue;
-    NSRect buttonFrame = [button frame];
-    buttonFrame.origin.x = xOffset;
-    [button setFrame:buttonFrame];
+    if (![button isBeingDragged])
+      [self moveButton:button toIndex:i animate:animate];
     ++i;
   }
 }
@@ -587,6 +605,49 @@
   [item setImage:[button compositedImage]];
 }
 
+- (void)actionButtonDragging:(NSNotification*)notification {
+  if (![self chevronIsHidden])
+    [self setChevronHidden:YES inFrame:[containerView_ frame] animate:YES];
+
+  // Determine what index the dragged button should lie in, alter the model and
+  // reposition the buttons.
+  CGFloat dragThreshold = std::floor(kBrowserActionWidth / 2);
+  BrowserActionButton* draggedButton = [notification object];
+  NSRect draggedButtonFrame = [draggedButton frame];
+
+  NSUInteger index = 0;
+  for (ExtensionList::iterator iter = toolbarModel_->begin();
+       iter != toolbarModel_->end(); ++iter) {
+    BrowserActionButton* button = [self buttonForExtension:(*iter)];
+    CGFloat intersectionWidth =
+        NSWidth(NSIntersectionRect(draggedButtonFrame, [button frame]));
+
+    if (intersectionWidth > dragThreshold && button != draggedButton &&
+        ![button isAnimating]) {
+      toolbarModel_->MoveBrowserAction([draggedButton extension], index);
+      [self repositionActionButtonsAndAnimate:YES];
+      return;
+    }
+    ++index;
+  }
+}
+
+- (void)actionButtonDragFinished:(NSNotification*)notification {
+  [self showChevronIfNecessaryInFrame:[containerView_ frame] animate:YES];
+  DCHECK(![[notification object] isBeingDragged]);
+  [self repositionActionButtonsAndAnimate:YES];
+}
+
+- (void)moveButton:(BrowserActionButton*)button
+           toIndex:(NSUInteger)index
+           animate:(BOOL)animate {
+  CGFloat xOffset = kGrippyXOffset +
+      (index * (kBrowserActionWidth + kBrowserActionButtonPadding));
+  NSRect buttonFrame = [button frame];
+  buttonFrame.origin.x = xOffset;
+  [button setFrame:buttonFrame animate:animate];
+}
+
 - (void)browserActionClicked:(BrowserActionButton*)button {
   int tabId = [self currentTabId];
   if (tabId < 0) {
@@ -669,7 +730,7 @@
         nil];
   }
   [chevronAnimation_ setViewAnimations:
-      [NSArray arrayWithObjects:animationDictionary, nil]];
+      [NSArray arrayWithObject:animationDictionary]];
   [chevronAnimation_ startAnimation];
 }